Search results for "Materiali"
showing 10 items of 876 documents
Mode I fracture toughness behavior of hydro-thermally aged carbon fibre reinforced DGEBA-HHPA-PES systems
2012
In this work the Mode I fracture toughness behavior of unidirectional CFRP laminates is investigated by means of Double Cantilever Beam (DCB) tests. The composite samples were manufactured by thermal curing after impregnation of a Carbon fabric with a DGEBA epoxy and anhydride HHPA curing agent. One resin batch was also mixed with a PES thermoplastic monomer to enhance the matrix toughness. Two lots of samples, toughened and un-toughened, were then left to soak in hot water to achieve various degrees of aging. The influence of matrix toughening and hydrothermal aging on the delamination behavior of the composite have then been assessed and correlated with characterization data from Dynamic …
Characterization of ultra-high-molecular-weight polyethylene (UHMWPE) modified by ion implantation
2004
Abstract Surface modification of ultra high molecular weight polyethylene (UHMWPE) is induced by ion implantation of different ions at 300 keV energy. The aim of this work was the chemical, physical and mechanical characterization of the modified material in order to know deep inside about the effect of the ion beam upon the polymer. The irradiated surfaces are investigated by Raman spectroscopy, infrared absorption and micro-hardness analysis, scanning electron microscopy. Pin on disc measurements valuated the wear of the UHMWPE against a stainless steel probe; wear resistance increases of about 76% after the ion implantation. This result can be attributed to the ion bombardment inducing a…
TI: Cyclophosphazenes as polymer modifiers
2003
The utilization of cyclophosphazenes as polymer modifiers is reviewed, with particular concern to their exploitation as versatile chain extenders, possibly for recycle problems, crosslinkers, to enhance mechanical properties of polymeric materials, branchers, to selectively introduce ramifications in linear polymers, and compatibilizers, to favor the formation of blends between originally incompatible organic macromolecules. The great versatility of the synthetic methods put forward for these substrates, together with the ease of controlling their modification, functionalization and reactivity are important parameters for the evaluation of which type of use is more feasible for these trimer…
Sustainable recycling technologies for thermoplastic polymers and their composites: A review of the state of the art
2022
This review article discusses the environmental and economic effects of recycling, as well as sustainable thermoplastic polymer recycling technologies. Several researchers have utilized recycled thermoplastics as matrices in the production of a variety of natural and synthetic-based composites, which is also the focus of this study. All of the industries (food and packaging, construction and building, transportation, and indoor usage) where recycled thermoplastics have a large market share (food and packaging, construction and building, transportation, and indoor usage) are covered in this review. The desirable properties of thermoplastic polymers, such as corrosion resistance, low density,…
Sharing practices in the digital age: inclusive processes and new citizens in the intelligent city
2015
Il modello smart city sta diventando un nuovo approccio di vita basato su processi inclusivi e pratiche innovative che coinvolgono cambiamenti correlati alle sfide delle città. I drivers (energia, mobilità, economia,etc..) della smart city sono realmente collegati dalla componente ICT che connette tutto in una logica omni-inclusiva. Attori e utilizzatori finali di queste trafsormazioni sono i cittadini, persone che con i loro smart phones diventano sensori della città recettiva e sensibile. La città in tempo reale viene analizzata attraverso mappe prodotte con sistemi GIS offrendo un altro modo di leggere le nuove funzioni urbane. E’ possibile quasi immediatamente attraverso App dedicate co…
On the mechanism of compatibilization of polyolefin/liquid crystalline polymer blends with graft copolymers
2000
The compatibilization mechanism of some compatibilizers for blends of polyolefins with a liquid crystalline polymer (LCP) was studied. Polyethylene (PE) and polypropylene (PP) were blended with a semirigid LCP (SBH) in a batch mixer, either with and without compatibilizers. The latter were two commercially available samples of functionalized polyolefins, that is, a PE-g-MA (HDM) and a PP-g-AA (Polybond 1001) copolymer and some purposely synthesized PE-g-LCP and PP-g-LCP copolymers. Microtomed films of the binary and the ternary blends were annealed at 240 degrees C on the hot stage of a polarizing microscope and the changes undergone by their morphology were recorded as a function of time. …
Behavior of Calcium Phosphate–Chitosan–Collagen Composite Coating on AISI 304 for Orthopedic Applications
2022
Calcium phosphate/chitosan/collagen composite coating on AISI 304 stainless steel was investigated. Coatings were realized by galvanic coupling that occurs without an external power supply because it begins with the coupling between two metals with different standard electrochemical potentials. The process consists of the co-deposition of the three components with the calcium phosphate crystals incorporated into the polymeric composite of chitosan and collagen. Physical-chemical characterizations of the samples were executed to evaluate morphology and chemical composition. Morphological analyses have shown that the surface of the stainless steel is covered by the deposit, which has a very r…
Effectiveness of Preservative Treatments on Coloured Ruditic Building Stones
2009
: The dark grey Breccia di Billiemi and the Ammonitico Rosso of Piana degli Albanesi, two coloured stones widely used in monuments both outdoor and indoor in Sicily, undergo significant decay as effect of weathering: colour change and development of surface microcracks which affect not only the chromatic aspect but also the state of aggregation. In a previous study (Fracture and Failure of Natural Building Stones, 2006, Springer, Dordrecht, The Netherlands: 329), such effects were successfully reproduced on laboratory samples by means of artificial accelerated weathering and the different response of veins and grains to the ageing agents was related to the microstructure of stones. In this…
AMBIENTE COSTRUITO E SOSTENIBILITÀ – Materiali riciclati e Design for Disassembly tra ricerca e buone pratiche
2020
In the context of environmental emergency of which the construction sector is one of the main causes – since it consumes 40% of the (embodied and operational) energy and produces about a third of the total waste – and due to the ambitious objectives set by the international community and by many countries to reduce the environmental impact of buildings during their whole life cycle, this paper wants to make a contribution to the understanding of the state of the art on cycle-based research activities, sustainable experiments and good practices that the building industry and the academy have implemented in recent years. In particular, it refers to cycle-based theoretical and experimental act…
Dettagli d’autore. Dal disegno manuale dei grandi maestri a quello digitale delle Archistar
2019
Il presente saggio offre un momento di riflessione critica sul dettaglio architettonico indagandone le potenzialità espressive e comunicative quando restituisce la prima idea del progettista o quando, come elemento o componente, concorre alla struttura-zione e alla caratterizzazione dell’opera. Attraverso la letteratura di riferimento, l’uso diffuso delle tecnologie digitali e le più recenti ricerche sul tema, si approfondiranno i ruoli e le criticità che il dettaglio ha come interfaccia per la comprensione dell’intero sistema costruttivo e per la caratterizzazione delle architetture nel prossimo futuro This essay offers a moment of critical reflection on architectural detail by investigati…